David Kestenbaum

Steve Barrett
/ N/A

David Kestenbaum is a correspondent for NPR, covering science, energy issues and, most recently, the global economy for NPR's multimedia project Planet Money. David has been a science correspondent for NPR since 1999. He came to journalism the usual way — by getting a Ph.D. in physics first.

In his years at NPR, David has covered science's discoveries and its darker side, including the Northeast blackout, the anthrax attacks and the collapse of the New Orleans levees. He has also reported on energy issues, particularly nuclear and climate change.

David has won awards from the American Association for the Advancement of Science, the American Physical Society and the Institute of Electrical and Electronics Engineers.

David worked briefly on the show This American Life, and set up a radio journalism program in Cambodia on a Fulbright fellowship. He also teaches a journalism class at Johns Hopkins University.

David holds a bachelor's of science degree in physics from Yale University and a doctorate in physics from Harvard University.

Take a look at your signature the next time you buy something with a credit card. Maybe you spell out every letter. Maybe you just put a squiggly line. The other day, I drew a tree.

Signing is a very old ritual, according to Rabbi Pinchas Allouche. He's a scholar of the Talmud, a collection of Jewish texts that's over 1,000 years old.

The Talmud not only mentions signatures; it has rules for them. "A scribble is prohibited," Allouche says. The name has to be legible. "Just yesterday, when signing a Toys R Us receipt, I thought of the Talmud," he says.

The other day I went down to the little shop in the lobby of our building for a snack. I couldn't decide whether I wanted regular M&M's or Peanut Butter M&M's so I bought them both. On the way back upstairs to the office, I noticed something strange on the labels. Each had cost $1, but the pack of Peanut Butter M&M's was a very tiny bit lighter: 0.06 ounces lighter!

I wanted to know why, so I called a couple of experts and asked for their theories:

Now, there's a curious fact about the Tappan Zee Bridge that President Obama was standing next to today. It's located at a spot where it seems to make the least economic sense to place a bridge - one of the widest parts of the Hudson River. Three years ago, David Kestenbaum of our Planet Money team dug into this. Here's an encore presentation of his report.